内部类不能访问外部类的变量吗？

[Quester-King]

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class InformationTable extends JTable {

	public InformationTable(AlterPanel alterPanel) {
		super(new ResultTableModel());
		
		this.getTableHeader().setReorderingAllowed(false);
		this.addMouseListener(new MouseAdapter() {
			public void mouseClicked(MouseEvent me) {
				int rowIndex = getSelectedRow();
				JTextField[] fieldList = { alterPanel.getIdField(),
						alterPanel.getNameField(), alterPanel.getSexField(),
						alterPanel.getBirthField(), alterPanel.getClassField(),
						alterPanel.getDepartmentField() };
			}
		});
	}

}

为什么下面那段代码总是报错？

JTextField[] fieldList = { alterPanel.getIdField(),
						alterPanel.getNameField(), alterPanel.getSexField(),
						alterPanel.getBirthField(), alterPanel.getClassField(),
						alterPanel.getDepartmentField() };

报错是：Cannot refer to a non-final variable alterPanel inside an inner class defined in a different method

为什么呢？

[RDroid]

public InformationTable(final AlterPanel alterPanel)